Glossary: M

The average height of the sea surface, based upon hourly observation of the tide height on the open coast or in adjacent waters that have free access to the sea. In the United States, it is defined as the average height of the sea surface for all...

a solid mass of mineral or rock matter that has fallen to the earth's surface from outer space without being completely vaporized in the atmosphere. Source: NASA (http://earthobservatory.nasa.gov/Glossary)

A hydrocarbon that is a greenhouse gas. Methane is produced through anaerobic (without oxygen) decomposition of waste in landfills, animal digestion, decomposition of animal wastes, production and distribution of natural gas and oil, coal production...

One thousandth of a bar, a unit of atmospheric pressure. The average atmospheric pressure at sea level is 1.01325 bars or 1013.25 mb. See pascal (Pa), atmospheric pressure. Source: NASA (http://earthobservatory.nasa.gov/Glossary)

The lessening or limitation of the adverse impacts of hazards and related disasters.
In UN-SPIDER Mitigation is used to encompass those measures aimed at reducing the exposition to a hazard and vulnerability

A mathematical representation of a process, system, or object developed to understand its behavior or to make predictions. The representation always involves certain simplifications and assumptions. Source: NASA (http://earthobservatory.nasa.gov/...

A name for seasonal winds, first applied to the winds over the Arabian Sea that blow for six months from the northeast and for six months from the southwest. The term has been extended to similar winds in other parts of the world (i.e., the...